Single-acting hot-gas reciprocating engine



Feb.

J. W. L. KQHLER SINGLE-ACTING HOT-GAS RECIPROCATING ENGINE Filed Sept. 15, 1953 p 1h M hm,

INVENTOR V JACOB WILLEM LAURENS KOHLER AGENT 2,872,779 SINGLE-ACTING HOT-GAS RECIPROCATING ENGINE Jacob Willem Laurens Kiihler, Eindhoven, Netherlands, assignor, by mesue assignments, to North American Philips Company, Inc, New York, N. Y., acorporation of Delaware Application September 15, 1953, Serial No. 380,335

Claims priority, application Netherlands September 24, 1952 1 'Claim. (CI. 60-24) With reciprocating engines comprising pistons and connecting rods coupled herewith directly or indirectly, it is common practice to provide the lightest possible construction for the head of the connecting rod, co-operating with a crank of a crank shaft. One of the reasons why this head is constructed so as to be as light as possible is that it is desirable to keep the acceleration forces low.

However, in a single-acting hot-gas reciprocating engine, comprising a cylinder and a piston and displacer piston moving therein and coupled both by means of connecting rods with cranks of a shaft, the connecting rod of the displacer piston gives rise to a problem differing from that in other reciprocating engines, since, compared with the piston, the displacer piston does no work or very little Work, since it is the function of the displacer piston to displace a given quantity of medium without compression or expansion. The displacer piston itself may be of very light construction, but the mass forces of the reciprocating parts produced during the motion of the displacer piston may, nevertheless, be comparatively great, particularly in high-speed engines. At each half revolution of the crank shaft the direction of the mass forces reverses. The displacer piston is, moreover, subjected to gas forces and frictional forces produced by the flow of gas and also reversing each time their sense. For the aforesaid .reasons the direction of the resultant force exerted on the crank pin is also reversed at each revolution of the crank shaft. the crank co-operating herewith exhibit a certain amount of play, clatter is produced and during operation wear of the head of the connecting rod and of the crank pin may occur in addition. According to the invention these disadvantages may be obviated, if in an apparatus of the aforesaid kind the end of the connecting rod of the displacer piston coupled with the shaft is proportioned to be such that during operation the radial component of the resultant force exerted on the crank maintains constantly the same sense. Therefore, in accordance with the invention and in contradistinction to actual common practice, for example the head of the connecting rod may be constructed to be heavier than is required. Since, in view of the low power to be produced by the displacer piston the connecting rod may normally be of very light construction and, as stated above, the displacer piston is not a heavy body either, the head of the connecting rod, made heavier in accordance with the invention, will not bring about an excessively great resultant force on the crank.

In order that the invention may be readily carried into efiect, it will now be described with reference to the acnitcd States atent If the connecting rod and 2,872,779 Patented Feb. 10, 1959 companying drawing, which shows one embodiment of the invention and in which Fig. 1 is a diagrammatical sectional view of a hot-gas reciprocating engine and Fig. 2 is a diagram of the forces exerted on the displacer piston and the crank pin during one revolution.

Reference numeral 1 designates a cylinder of a singleacting hot-gas reciprocating engine, the upper end of which comprises a conventional heater 2, a regenerator 3 and a cooler 4. In the cylinder 1 are adapted to reciprocate a piston 5 and a displacer piston 6. The latter is provided with a rod '7, which is coupled by means of a simple clutch 8 with a connecting rod 9. The piston 5 is coupled through two connecting rods 10 with cranks 11 of a crank shaft 12. This crank shaft supports a third crank 14, which is at right angles to the cranks 11 and with which the connecting rod 9 of the displacer piston is coupled by means of a connecting-rod head 13. This head is made so heavy, in accordance with the invention, that, if the hot-gas reciprocating engine is operative, the radial component of the resultant force exerted on the crank remains active in the same sense, so that any small amount of play between the head 13 and the crank pin 14 does not give rise to clattering. During a revolution the play is shifted gradually, as is evident from Fig. 2. In this figure reference numeral 15 designates the circle on which the center of the crank pin of the crank 14 moves during one revolution and on four points equally distributed around the circle are indicated with dash-dot lines 16 the instantaneous value and the direction of the resultant force, acting on the crank. This resultant force is composed in known manner of the tangential component 16a of the force 1611, occurring in the displacer piston and drawn with a broken line and the radial component 16c of this force, which latter is combined with the centrifugal force 16d of the enlarged end 15 of crank pin 13, the latter being made heavier in accordance with the invention and which is drawn with a heavy line. The angle which the displacer connecting rod makes in four points with the vertical is indicated by the direction of the lines 16. It appears that the radial component 16c+16d remains operative in the same direction relative to the crank so that any clearance space between the enlarged end of the connecting rod and the crank pin moves around with the crank pin, so that no clatter can occur.

What is claimed is:

A single-acting hot-gas reciprocating engine comprising a cylinder, a piston and a displacer mounted for reciprocable movement in said cylinder, a crankshaft, crank and connecting rod means connecting both said piston and displacer to said crankshaft, the displacer and piston both having crank heads, the crank head of said displacer being heavier than the crank heads of said piston, said heavy crank head being at the end of the connecting rod connecting said displacer with said crankshaft and being of such dimensions that during operation of the displacer the radial component of the resultant force exerted on the crank means remains continually operative in the same direction thereby preventing clattering between said crank pin and said heavy crank head.

Rinia et al Dec. 26, 1950 Liebe Nov. 4, 1952 

